DE102006022572A1 - Milling tool for machining e.g. sandwich-like designed material composite board, has peripheral blades, whose cutting geometry changes in peripheral direction from one blade to another blade with same cutting direction in opposite direction - Google Patents

Abstract

The tool (10) has a cylindrical shaft (12), and a cutting part (14) including large cutting bars (18a, 18b,18d) with respective helically running peripheral blades (20, 22), where the cutting bars are arranged equidistant by grooves (16a, 16b) in a peripheral direction. The cutting geometry of one of the peripheral blades changes in the peripheral direction from the blade to another blade with same cutting direction in an opposite direction. The grooves run parallel to a rotation axis of the tool, which is made of a full hard metal.

Description

The The invention relates to a milling tool for machining in particular fiber-reinforced composite material boards.

by virtue of a high tensile strength, but at the same time a low weight find fiber reinforced composite panels as suitable lightweight materials especially in the aerospace industry Application. For the outer skin For example, modern aircraft are sandwiched Composite materials used, which is a layer of carbon fiber reinforced plastic (CFRP), a layer of titanium and another layer of aluminum have, wherein the layers can be arranged differently.

Indeed stand the above-mentioned advantages a relatively difficult workability the fiber reinforced Composite material panels by milling opposite. So occur in the milling of fiber reinforced Composite material panels, for example during milling the edges of already prefabricated boreholes, often delamination and temperature damage. Delamination refers to the extraction of individual fibers from the Fiber composite as a result of destruction the same by the milling. With increasing wear of the milling tool be in the area of the cut surface projecting fibers of the fiber composite then no longer correct cut, but only knocked off due to the cutting pulse. This force on the fiber composite ultimately leads to fraying the edges of the machined boreholes. In addition to delamination learns the composite material plate above addition, a local warming in the area of the cut surfaces the fiber composite due to the cutting forces or with increasing wear of the milling tool by friction between the milling tool and the workpiece. This warming In the worst case, it may cause the epoxy resin of the matrix to flow the fiber composite and thus to a bonding of the milling during machining resulting dust on the cut surfaces of Fa serverbundes lead. Of Furthermore, such milling conditions go at the expense of the service life of the milling tools.

In front In this background, the invention is based on the object milling tool to create that for himself the processing fiber reinforced Composite material panels, in particular sandwich-like composite composite panels with a layer of carbon fiber reinforced plastic (CFRP).

Is solved this task by a milling tool with the features of claim 1 or 3. Advantageous and / or preferred developments are the subject of dependent claims.

According to the invention Cutting geometries of the peripheral cutting on the cutting webs of in a predetermined direction cutting milling tool configured so that their sense of direction during of the cutting process, i. at the same cutting direction, in the way it changes, that for example a composite material plate and thus a in the composite material board containing fiber reinforced plastic layer, e.g. CFRP layer, opposing axial acting cutting forces experiences. The Cutting force per peripheral edge can be with respect to the Rotary axis of the milling tool in an axially acting cutting force component and a Disassemble cutting force acting in the cutting direction. The cutting geometries of Circumferential cutting of the milling tool are designed so that the axially acting cutting force shares two peripheral cutting edges with opposing cutting geometry in opposite directions, preferably directed against each other, oriented. This will achieved that the composite material plate, in particular the fiber-reinforced plastic plate, acting both in one and in the other axial direction of the milling tool cutting forces (specifically: average shares) learns. This will be individual Fibers from the fiber composite of the fiber-reinforced plastic layer reliably cut off. A detachment and beating off individual fibers from the fiber composite and thus fraying the composite material plate can with the milling tool according to the invention thus restricted become.

According to claim 1, the cutting part an even number greater than or equal to four, ie four, six, eight, etc., of circumferentially spaced by grooves cutting webs, each with at least one helically extending peripheral edge. In this embodiment, the twisting direction of the cutting geometry of the at least one circumferential cutting edge changes in the circumferential direction from cutting web to cutting web in opposite directions, ie from a left twist to a right twist and vice versa, with the same cutting direction. Due to the even number greater than or equal to four of the cutting bars is achieved that the generated by the helically extending peripheral cutting with opposite cutting geometry axial Schnittkraftanteile temporally offset relatively short acting on the machined composite plate, with the result that excessive mechanical and thermal stress on the peripheral cutting within limits ge can be kept. In addition, it is ensured by this embodiment, that the axial cutting force components of the cutting edge located in milling during full cutting in the sum always cancel out.

In The development according to claim 2 is provided that the opposing Cutting geometries are arranged offset axially. For example is a left-handed cutting geometry on one side formed the shaft lying portion of the respective cutting web, while a rechtsgedrallte cutting geometry at one on the side of the Fräswerkzeugkopfs lying portion of the respective cutting ridge is formed. The left- and right-dished cutting geometries can be found in Axial direction of the milling tool considered separately, i. with or without distance, or in overlap be arranged.

To the claim 3, the cutting part a number, preferably one even number greater than or equal four, spaced circumferentially by grooves cutting webs on. The cutting webs are each in two axial sections with each at least one helical run divided the peripheral edge. In this embodiment changes the twisting direction of the cutting edge geometry of the at least one peripheral cutting edge from one of the two axial sections of one cutting bar to the other the two axial sections of the same cutting web in opposite directions, i.e. from a left twist to a right twist and vice versa, at same cutting direction. This embodiment ensures that the through the peripheral cutting with opposite cutting geometry generated oppositely oriented axial cutting force shares always at the same time act on the processed composite material plate. If the cutting ridges in an even number greater equal four are provided, can be an excessive mechanical and thermal stress on the peripheral cutting is limited become.

In The development according to claim 4 is provided that the cutting geometry the at least one peripheral edge of the on the side of the shaft lying left axial portion and the cutting edge geometry the at least one peripheral cutting edge of the on the side of the Fräswerkzeugkopfs lying axial portion is right-dished.

In The development according to claim 5, the twisting direction the cutting geometries of the peripheral cutting of the two axial Reverse sections from cutting land to cutting land.

In The development according to claim 6, the cutting ribs in the circumferential direction essentially equidistant spaced apart. This will cause the barrel of the milling tool calmed down. It can - deviating of it - too Jetty pairs equidistant be arranged, wherein each pair of webs peripheral cutting with opposite directions Cutting geometry can have. The angular distance between two cutting webs a Schneidstegpaares can regardless of the angular distance of Bridge pairs are set.

in the Sense of a possible uniform cutting force curve and a good chip and material removal point the cutting webs in the development according to claim 7 each have a variety of in equidistant axial division arranged on peripheral cutting. If at the same time several cutting edges are engaged, the cutting forces per cutting edge decrease, resulting in better surface accuracy and get a calmer run

In The development according to claim 8, the grooves are parallel to the axis of rotation of the milling tool.

In The development according to claim 9 extend the cutting edges the peripheral cutting at an angle of 50 ° to 60 °, preferably 53 to 57 °, relative to the Rotary axis of the milling tool. For the Processing of the composite material board are generally possible low cutting forces sought. Advantages of low cutting forces include higher geometric ones Accuracy, lower machine power and energy consumption, one Protection of the composite material board and the milling tool and a better Surface quality and a less static and dynamic machine load.

In The development according to claim 10, the shaft and the cutting part one piece educated.

In The development according to claim 11 is the milling tool made of solid carbide.

The cross section of the cutting wedge of the peripheral cutting is ge to maximum wear and ge a web in the direction of open space designed. To increase the service life and maintain the Schnittfreudigkeit the milling tool, a wear protection coating is additionally provided in the development according to claim 11 at least in the region of the cutting part. By the interplay of the cutting geometry according to the invention with the wear protection layer, a delamination-free processing of composite material boards can be obtained with a fiber-reinforced plastic layer.

Further constructive details will become apparent from the following description preferred embodiments in conjunction with the drawings in which:

1 a side view of a milling tool according to the invention according to a first embodiment shows;

2 shows a plan view of the head of the milling tool according to the invention according to the first embodiment;

3 shows a side view of the cutting part of the milling tool according to the invention according to the first embodiment;

4a and 4b each show a section for illustrating the cutting wedge shapes of the peripheral cutting edges of two cutting webs of the milling tool according to the invention according to the first embodiment;

5 a side view of a milling tool according to the invention according to a second embodiment shows;

6 shows a plan view of the head of the milling tool according to the invention according to the second embodiment;

7 shows a side view of the cutting part of the milling tool according to the invention according to the second embodiment;

8a and 8b show in each case a section for illustrating the cutting wedge shapes of the peripheral cutting edges of a cutting web of the milling tool according to the invention according to the second embodiment;

9 a side view of a milling tool according to the invention according to a third embodiment shows; and

10 a side view of a milling tool according to the invention according to a fourth embodiment shows.

First embodiment

1 shows a straight-grooved, right-hand cutting tool 10 according to a first embodiment with a cylindrical shaft 12 and a cutting part 14 , The milling tool 10 is made in one piece from solid carbide and has a friction and / or wear-reducing surface protection coating.

The cutting part 14 shows how out 2 is visible, four, in the circumferential direction by grooves 16a . 16b . 16c . 16d equidistantly spaced cutting ribs 18a . 18b . 18c . 18d on. Every cutting bridge 18a . 18b . 18c . 18d defines a plurality of axially in equidistant pitch T (see 3a . 3b ) arranged peripheral cutting edges 20 respectively. 22 ,

As it turned out 1 . 3 . 4a and 4b results, the sense of direction of the cutting edge geometry of the peripheral cutting changes 20 . 22 in the circumferential direction of the milling tool 10 from cutting bar to cutting bar. While the cutting edge geometries of the cutting edges 18a and 18c trained peripheral cutting 20 have a Rechtsdrall, have the cutting edge geometry of the cutting webs 18b and 18d trained peripheral cutting 22 a left twist on.

The cross section of the cutting wedge shapes of the peripheral cutting edges 20 the cutting bridges 18a and 18c is in 4a illustrated. The cross section of the cutting wedge shapes of the peripheral cutting edges 22 the cutting bridges 18b and 18d is in 4b illustrated. How out 4a and 4b is clearly visible, are the cutting wedges of the peripheral cutting 20 against the cutting wedges of the peripheral cutting 22 directed.

The following table shows the parameters determining the cutting geometry for the right-hand peripheral cutting edges 20 and the left-handed peripheral cutters 22 as well as other parameters of the milling tool 10 summarized according to the first embodiment: L 112.8 mm L1 70.5 mm L2 28.2 mm D 16.9 mm D2 17.9 mm D 10.6 mm B 5.7 mm α 57 °

Second embodiment

5 shows a straight-grooved, right-hand cutting tool 100 according to a second embodiment with a cylindrical shaft 112 and a cutting part 114 , The milling tool 100 is made in one piece from solid carbide and has a friction and / or wear-reducing surface protection coating.

The cutting part 114 shows how out 6 is visible, four, in the circumferential direction by grooves 116a . 116b . 116c . 116d equidistantly spaced cutting ribs 118a . 118b . 118c . 118d on. Every cutting bridge 118a . 118b . 118c . 118d has two axial sections 118a1 and 118a2 . 118b1 and 118b2 . 118c1 and 118c2 respectively. 118d1 and 118d2 on. Each of these axial sections defines a plurality of axially equidistant pitch T (see FIG 8a . 8b ) arranged peripheral cutting edges 120 respectively. 122 ,

As it turned out 5 . 7 . 8a and 8b results, the sense of direction of the cutting edge geometry of the peripheral cutting changes 120 . 122 each cutting bridge 118a . 118b . 118c . 118d in the axial direction of the milling tool 100 from the side of the head of the milling tool 100 lying axial section 118a1 . 118b1 . 118c1 respectively. 118d1 to the side of the shaft 112 lying axial section 118a2 . 118b2 . 118c2 respectively. 118d2 , While the cutting edge geometries of the at the head axial sections 118a1 . 118b1 . 118c1 respectively. 118d1 trained peripheral cutting 120 have a Rechtsdrall, have the cutting edge geometry of the shaft side axial sections 118a2 . 118b2 . 118c2 respectively. 118d2 trained peripheral cutting 122 a left twist on.

The cross section of the cutting wedge shapes of the peripheral cutting edges 120 is in 8a illustrated. The cross section of the cutting wedge shapes of the peripheral cutting edges 122 is in 8b illustrated. How out 8a and 8b is clearly visible, are the cutting wedges of the peripheral cutting 120 against the cutting wedges of the peripheral cutting 122 directed.

The following table shows the parameters determining the cutting geometry for the right-hand peripheral cutting edges 120 and the left-handed peripheral cutters 122 as well as other parameters of the milling tool 100 summarized according to the second embodiment: L 112.8 mm L1 70.5 mm L2 28.2 mm L3 14.1 mm D 16.9 mm D2 17.9 mm d 10.6 mm B 5.7 mm α120 57 ° α122 57 °

Third embodiment

9 shows a straight-grooved, right-hand cutting tool 200 according to a third embodiment, which differs from the milling tool according to the first embodiment only in that the peripheral cutting edges 220 and 222 formed with opposing cutting geometries not over the full length of the respective cutting web but only over desse half length and thus arranged axially offset. According to 9 are the peripheral cutting edges 222 of the cutting bridge 218d , which have a left-handed cutting geometry, on the side of the shaft 212 lying half length of the cutting land 218d limited, while the peripheral cutting 220 of the cutting bridge 218a having a right-handed cutting geometry, on the side lying on the side of the Fräswerkzeugkopfs half the length of the cutting web 218a are limited.

In 9 are the left and right winged peripheral cutting edges 222 and 220 in the axial direction of the milling tool 200 arranged one behind the other. Deviating from the left and right winged peripheral cutting edges 222 and 220 in the axial direction of the milling tool 200 but also be arranged with an axial distance one behind the other or in overlapping.

Fourth embodiment

10 shows a straight-grooved, right-hand cutting tool 300 according to a fourth embodiment, which differs from the milling tool according to the second embodiment only in that the swirl direction of the cutting edge geometries of the peripheral cutting edges of the two axial sections is reversed from cutting web to cutting web.

Further embodiments

The The above-illustrated first to fourth embodiments are currently preferred embodiments the milling tool according to the invention. Therefore, it should be noted that in particular the mentioned parameters concerning the cutting geometry of the peripheral cutting edges and the others Design no restriction of the invention of milling tool represent.

Claims (12)

Milling tool ( 10 ; 200 ) with a shaft ( 12 ; 212 ) and a cutting part ( 14 ; 214 ), characterized in that the cutting part ( 14 ; 214 ) an even number greater than or equal to four in the circumferential direction by grooves ( 16a - 16d ) spaced cutting webs ( 18a - 18d ) each having at least one helically extending peripheral cutting edge ( 20 . 22 ), and the cutting geometry of the at least one peripheral cutting edge ( 20 . 22 ) changes in the circumferential direction of cutting bar to cutting bar in the same direction in opposite directions. milling tool according to claim 1, characterized in that the opposing cutting geometries axially are arranged offset. Milling tool ( 100 ; 300 ) with a shaft ( 112 ) and a cutting part ( 114 ), characterized in that the cutting part ( 114 ) a number, preferably an even number greater than or equal to four, of circumferentially by grooves ( 116a - 116d ) spaced cutting webs ( 118a - 118d ), the cutting webs ( 118a - 118d ) each in two axial sections ( 118a1 - 118d2 ) each having at least one helically extending peripheral cutting edge ( 120 . 122 ), and the cutting geometry of the at least one peripheral cutting edge ( 120 . 122 ) changes in opposite directions from one of the two sections of a cutting web to the other of the two sections of the cutting web in the same cutting direction. milling tool according to claim 3, characterized in that the cutting geometry the at least one peripheral edge of the on the side of the shaft lying left portion and the cutting geometry of the at least one peripheral edge of the on the side of the Fräswerkzeugkopfs lying portion is rechtsgedrallt. Milling tool according to claim 3 or 4, characterized in that the swirl direction of Schnei the geometries of the peripheral edges of the two axial sections of cutting web to cutting web reverses. milling tool according to one of the preceding claims, characterized the cutting webs are substantially equidistant in the circumferential direction spaced apart. milling tool according to one of the preceding claims, characterized that the cutting bars each have a variety of in equidistant having axial pitch arranged peripheral cutting. milling tool according to one of the preceding claims, characterized the grooves run parallel to the axis of rotation of the milling tool. milling tool according to one of the preceding claims, characterized in that that the cutting edges of the peripheral cutting edges at an angle of 50 ° to 60 °, preferably 53 to 57 °, across from the axis of rotation of the milling tool run. milling tool according to one of the preceding claims, characterized that the shank and the cutting part are integrally formed. milling tool according to claim 10, characterized in that the milling tool are made of solid carbide. milling tool according to one of the preceding claims, characterized by a provided at least in the region of the cutting part wear protection coating.